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The Paleocene–Eocene thermal maximum (PETM), alternatively ”Eocene thermal maximum 1 (ETM1)“ and formerly known as the "Initial Eocene" or “Late Paleocene thermal maximum", was a geologically brief time interval characterized by a 5–8 °C global average temperature rise and massive input of carbon into the ocean and atmosphere.
The Paleocene–Eocene thermal maximum (PETM), alternatively ”Eocene thermal maximum 1 (ETM1)“ and formerly known as the "Initial Eocene" or “Late Paleocene thermal maximum", was a geologically brief time interval characterized by a 5–8 °C global average temperature rise and massive input of carbon into the ocean and atmosphere.
The most pronounced of these, the Paleocene-Eocene Thermal Maximum (PETM) is visible in the figure at right. These are usually interpreted as caused by abrupt releases of methane from clathrates (frozen methane ices that accumulate at the bottom of the ocean), though some scientists dispute that methane would be sufficient to cause the observed ...
The Paleocene–Eocene Thermal Maximum was an approximately 200,000-year-long event where the global average temperature rose by some 5 to 8 °C (9 to 14 °F), [55] and mid-latitude and polar areas may have exceeded modern tropical temperatures of 24–29 °C (75–84 °F). [108]
Methane has a very light δ 13 C signature: biogenic methane of −60‰, thermogenic methane −40‰. The release of large amounts of methane clathrate can affect global δ 13 C values, as at the Paleocene–Eocene Thermal Maximum.
the Danian-Selandian event at the transition between the Danian and Selandian stages of the Paleocene, about 61 million years ago; the two events following the PETM during the Eocene climatic optimum: the Eocene Thermal Maximum 2 (ETM2) about 53.2 million years ago, and the Eocene Thermal Maximum 3 (ETM3) about 52.5 million years ago. [2]
Paleocene–Eocene Thermal Maximum: 53.7: Eocene Thermal Maximum 2: 49: Azolla event may have ended a long warm period 5.3–2.6: Pliocene climate became cooler and drier, and seasonal, similar to modern climates. 2.5 to present: Quaternary glaciation, with permanent ice on the polar regions, many named stages in different parts of the world
The scientific field of paleoclimatology came to maturity in the 20th century. Notable periods studied by paleoclimatologists include the frequent glaciations that Earth has undergone, rapid cooling events like the Younger Dryas, and the rapid warming during the Paleocene–Eocene Thermal Maximum.